Each new test is leveled to make it easy for the teacher and parent to choose. The parents and teachers can purchase each new test based on what its level is, and the kids in the class can take tests from that level until they should that they should be doing something more difficult.
There are many workbooks that can be handed out to the kids, and these workbooks will support the tests that are being given. The workbooks and tests together create an entire course that the students can use to learn. Also, the workbooks can have the pages torn out to make sure that the students can show off their good work.
The courses that children take when they are in school will teach them a great many things, but they need to remember that their study begins and ends with those tests.